RESTING ENERGY EXPENDITURE IMPACTS ON SHORT- AND LONG-TERM MORTALITY IN CRITICALLY ILL PATIENTS AFTER CARDIAC SURGERY- A RETROSPECTIVE ANALYSIS

Abstract

<h3>Background</h3> It is well known that underfeeding and overfeeding of critically ill patients is harmful.¹ Even though it has been shown that administering nutrients at 70% of measured resting energy expenditure (REE) has a survival benefit, it was never assessed whether REE itself may be decreased in patients with adverse outcome. We therefore investigated whether REE measured via pulmonary artery catheter (PAC) impacts short- and long-term outcome after cardiac surgery comprising 30-day, 1-year and 1-6-year all-cause mortality. <h3>Methods</h3> We enrolled 596 consecutive patients who received a PAC prior to cardiac surgery for haemodynamic monitoring. Oxygen consumption (VO2) was determined from data obtained by the PAC during their ICU stay. REE was then calculated via the Fick equation and averaged over the first 7 days. Patients were divided into 2 groups depending on their REE being either above or below the median REE. Survival analysis was performed using the Kaplan Meier and multivariate Cox regression analysis for all-cause mortality. <h3>Results</h3> Patients with reduced REE, i.e., REE below the median of 1640 kcal/day, showed a significantly worse survival at 30-day and 1-year, but not for the period 1-6-years after cardiac surgery (Figure). In the multivariate cox regression, REE<=1640 remained an independent factor for worse survival after 1-year, even after adjusting for gender, age (4 groups <=55, 56-65, 66-75, >75), BMI (3 groups <=25, 26-30, >30) and length of surgery (2 groups <=6h, >6h) [REE<=1640: HR 2.2 (1.39; 3.51); (p<0.001)]. <h3>Conclusion</h3> Our findings indicate that reduced REE is associated with adverse outcome in patients after cardiac surgery emphasizing the importance of monitoring REE in critically ill patients either via indirect calorimetry or via PAC. Supplying nutrients based on calculated nutritional targets may cause overfeeding in vulnerable patients with reduced REE. <h3>References</h3> <ul><li>1. Zusman O, Theilla M, Cohen J, Kagan I, Bendavid I, Singer P. Resting energy expenditure, calorie and protein consumption in critically ill patients: a retrospective cohort study. Crit Care. 2016;20:367.</li></ul>